Many pharmaceuticals to be administered in liquid form via a syringe to a patient are delivered in the form of a dry substance to hospitals, because e.g. better stability of the pharmaceuticals is achieved in this way. However, a drug in the form of a dry substance has to be dissolved in a liquid at the hospital, e.g. if the drug is intended to be administered in liquid form via a medical syringe to a patient. Normally, the dissolving is done by filling liquid-proof dissolving receptacles closed by a cap and containing the pharmaceutical substance ready in powder form, with sterilized water in a content corresponding to the required mixing ratio, by the same medical syringe via which the pharmaceutical substance is to be administered to a patient later on. For this purpose, each dissolving receptacle contains the powdered/pulverized pharmaceutical substance dosed in a quantity that corresponds to the quantity of the liquid drug prescribed to the patient. After the addition of sterilized water, the dissolving receptacle is shaken in such a way that the powdered/pulverized pharmaceutical substance is mixed and dissolved in the added liquid. The shaking is performed for a suitable time in a continuous or, for example, intermittent manner by allowing the mixed solution that contains the powder to settle now and then. This step normally takes about 1 to 2 minutes, after which the mixture is still allowed to settle and become clearer in a slightly longer settling step. After this, the pharmaceutical substance is removed from the dissolving receptacle to the medical syringe by using the same needle with which the water was added to the dissolving receptacle. Next, the needle used in the mixing step is removed from the medical syringe and replaced by a sealed and sterile cap at the tip of the syringe. After this, the medical syringe is normally equipped with a label indicating the data of the recipient of the drug, as well as the name and the dose of the pharmaceutical substance to be administered. Finally, the medical syringe is placed in a location where a doctor or nurse delivering the drugs will pick up the ready-prepared medical syringe.
The manual preparation of medical syringes requires careful and precise handling of drug packages, dissolving receptacles and medical syringes, to prevent contamination of the pharmaceutical substance by viruses and bacteria. The preparing person should, for example, ensure proper disinfection of his/her hands before handling drug packages, dissolving receptacles and medical syringes. In a large hospital, it may be necessary to prepare hundreds of such medical syringes daily; consequently, the manual dissolving requires the labour input of several persons. To alleviate this situation, fully automatic apparatuses have recently entered the market, for dissolving a powdered or pulverized pharmaceutical substance in a liquid (sterilized water) and for preparing medical syringes ready without manual work. One such apparatus of prior art typically comprises a weighing device, a device for adding a solution, a mixing device, a device for filling a syringe, a device for removing a needle used for filling a syringe, a device for fastening a cap to the tip of a syringe, as well as a device for attaching a label to a syringe. For transferring a dissolving receptacle and a syringe from one device to another, an industrial robot is used which applies its gripper to grip a receptacle and a syringe to be transferred from one device to another, and places and holds them in a desired location, if necessary. The robot also applies the medical syringe, that is, moves the plunger part of the medical syringe in a given direction with respect to its cylinder part.
In methods and apparatuses of prior art for automatic dissolving of powdered or pulverized pharmaceuticals and for preparation of medical syringes, a number of separate devices are used for implementing the handling steps, each device having a specific function. Moreover, these apparatuses function slowly, because the application of the medical syringes, i.e. the moving of the plunger part of the medical syringe with respect to the cylinder part, is implemented by all too clumsy and slowly operating special equipment. In addition, the methods and apparatuses of prior art are inefficient, because they are capable of handling only one dissolving receptacle and one medical syringe at a time.